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Tosi F, Roatsch T, Galli A, Hauber E, Lucchetti A, Molyneux P, Stephan K, Achilleos N, Bovolo F, Carter J, Cavalié T, Cimò G, D’Aversa E, Gwinner K, Hartogh P, Huybrighs H, Langevin Y, Lellouch E, Migliorini A, Palumbo P, Piccioni G, Plaut JJ, Postberg F, Poulet F, Retherford K, Rezac L, Roth L, Solomonidou A, Tobie G, Tortora P, Tubiana C, Wagner R, Wirström E, Wurz P, Zambon F, Zannoni M, Barabash S, Bruzzone L, Dougherty M, Gladstone R, Gurvits LI, Hussmann H, Iess L, Wahlund JE, Witasse O, Vallat C, Lorente R. Characterization of the Surfaces and Near-Surface Atmospheres of Ganymede, Europa and Callisto by JUICE. SPACE SCIENCE REVIEWS 2024; 220:59. [PMID: 39132056 PMCID: PMC11310297 DOI: 10.1007/s11214-024-01089-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 07/01/2024] [Indexed: 08/13/2024]
Abstract
We present the state of the art on the study of surfaces and tenuous atmospheres of the icy Galilean satellites Ganymede, Europa and Callisto, from past and ongoing space exploration conducted with several spacecraft to recent telescopic observations, and we show how the ESA JUICE mission plans to explore these surfaces and atmospheres in detail with its scientific payload. The surface geology of the moons is the main evidence of their evolution and reflects the internal heating provided by tidal interactions. Surface composition is the result of endogenous and exogenous processes, with the former providing valuable information about the potential composition of shallow subsurface liquid pockets, possibly connected to deeper oceans. Finally, the icy Galilean moons have tenuous atmospheres that arise from charged particle sputtering affecting their surfaces. In the case of Europa, plumes of water vapour have also been reported, whose phenomenology at present is poorly understood and requires future close exploration. In the three main sections of the article, we discuss these topics, highlighting the key scientific objectives and investigations to be achieved by JUICE. Based on a recent predicted trajectory, we also show potential coverage maps and other examples of reference measurements. The scientific discussion and observation planning presented here are the outcome of the JUICE Working Group 2 (WG2): "Surfaces and Near-surface Exospheres of the Satellites, dust and rings".
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Affiliation(s)
- Federico Tosi
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Thomas Roatsch
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - André Galli
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Bern, Switzerland
| | - Ernst Hauber
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Alice Lucchetti
- Istituto Nazionale di Astrofisica – Osservatorio Astronomico di Padova (INAF-OAPd), Padua, Italy
| | | | - Katrin Stephan
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Nicholas Achilleos
- Department of Physics & Astronomy, University College London, London, UK
| | - Francesca Bovolo
- Center for Digital Society, Fondazione Bruno Kessler (FBK), Trento, Italy
| | - John Carter
- Institut d’Astrophysique Spatiale (IAS), CNRS/Université Paris-Saclay, Orsay, France
| | - Thibault Cavalié
- Laboratoire d’Astrophysique de Bordeaux, Université de Bordeaux, CNRS, Pessac, France
- LESIA, Observatoire de Paris, Meudon, France
| | - Giuseppe Cimò
- Joint Institute for VLBI ERIC, Dwingeloo, The Netherlands
| | - Emiliano D’Aversa
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Klaus Gwinner
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Paul Hartogh
- Max Planck Institute for Solar System Research, Göttingen, Germany
| | - Hans Huybrighs
- Space and Planetary Science Center, Khalifa University, Abu Dhabi, UAE
- School of Cosmic Physics, Dunsink Observatory, Dublin Institute for Advanced Studies (DIAS), Dublin, Ireland
| | - Yves Langevin
- Institut d’Astrophysique Spatiale (IAS), CNRS/Université Paris-Saclay, Orsay, France
| | | | - Alessandra Migliorini
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Pasquale Palumbo
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Giuseppe Piccioni
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | | | - Frank Postberg
- Department of Earth Sciences, Freie Universität Berlin, Berlin, Germany
| | - François Poulet
- Institut d’Astrophysique Spatiale (IAS), CNRS/Université Paris-Saclay, Orsay, France
| | | | - Ladislav Rezac
- Max Planck Institute for Solar System Research, Göttingen, Germany
| | - Lorenz Roth
- Division of Space and Plasma Physics, KTH Royal Institute of Technology, Stockholm, Sweden
| | | | - Gabriel Tobie
- Laboratoire de Planétologie et Géosciences, Nantes Université, Nantes, France
| | - Paolo Tortora
- Department of Industrial Engineering (DIN), Università di Bologna, Forlì, Italy
| | - Cecilia Tubiana
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Roland Wagner
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Eva Wirström
- Chalmers University of Technology, Onsala, Sweden
| | - Peter Wurz
- Physics Institute, Space Research and Planetary Sciences, University of Bern, Bern, Switzerland
| | - Francesca Zambon
- Istituto Nazionale di Astrofisica – Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Rome, Italy
| | - Marco Zannoni
- Department of Industrial Engineering (DIN), Università di Bologna, Forlì, Italy
| | | | - Lorenzo Bruzzone
- Dipartimento di Ingegneria e Scienza dell’Informazione, Università degli Studi di Trento, Trento, Italy
| | | | | | - Leonid I. Gurvits
- Joint Institute for VLBI ERIC, Dwingeloo, The Netherlands
- Faculty of Aerospace Engineering, Delft University of Technology, Delft, The Netherlands
| | - Hauke Hussmann
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - Luciano Iess
- Dipartimento di Ingegneria Meccanica e Aerospaziale (DIMA), Università degli Studi di Roma “La Sapienza”, Rome, Italy
| | | | - Olivier Witasse
- European Space Agency – European Space Research and Technology Centre (ESA-ESTEC), Noordwijk, The Netherlands
| | - Claire Vallat
- European Space Agency – European Space Astronomy Centre (ESA-ESAC), Madrid, Spain
| | - Rosario Lorente
- European Space Agency – European Space Astronomy Centre (ESA-ESAC), Madrid, Spain
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2
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Blankenship DD, Moussessian A, Chapin E, Young DA, Wesley Patterson G, Plaut JJ, Freedman AP, Schroeder DM, Grima C, Steinbrügge G, Soderlund KM, Ray T, Richter TG, Jones-Wilson L, Wolfenbarger NS, Scanlan KM, Gerekos C, Chan K, Seker I, Haynes MS, Barr Mlinar AC, Bruzzone L, Campbell BA, Carter LM, Elachi C, Gim Y, Hérique A, Hussmann H, Kofman W, Kurth WS, Mastrogiuseppe M, McKinnon WB, Moore JM, Nimmo F, Paty C, Plettemeier D, Schmidt BE, Zolotov MY, Schenk PM, Collins S, Figueroa H, Fischman M, Tardiff E, Berkun A, Paller M, Hoffman JP, Kurum A, Sadowy GA, Wheeler KB, Decrossas E, Hussein Y, Jin C, Boldissar F, Chamberlain N, Hernandez B, Maghsoudi E, Mihaly J, Worel S, Singh V, Pak K, Tanabe J, Johnson R, Ashtijou M, Alemu T, Burke M, Custodero B, Tope MC, Hawkins D, Aaron K, Delory GT, Turin PS, Kirchner DL, Srinivasan K, Xie J, Ortloff B, Tan I, Noh T, Clark D, Duong V, Joshi S, Lee J, Merida E, Akbar R, Duan X, Fenni I, Sanchez-Barbetty M, Parashare C, Howard DC, Newman J, Cruz MG, Barabas NJ, Amirahmadi A, Palmer B, Gawande RS, Milroy G, Roberti R, Leader FE, West RD, Martin J, Venkatesh V, Adumitroaie V, Rains C, Quach C, Turner JE, O’Shea CM, Kempf SD, Ng G, Buhl DP, Urban TJ. Radar for Europa Assessment and Sounding: Ocean to Near-Surface (REASON). SPACE SCIENCE REVIEWS 2024; 220:51. [PMID: 38948073 PMCID: PMC11211191 DOI: 10.1007/s11214-024-01072-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 04/29/2024] [Indexed: 07/02/2024]
Abstract
The Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) is a dual-frequency ice-penetrating radar (9 and 60 MHz) onboard the Europa Clipper mission. REASON is designed to probe Europa from exosphere to subsurface ocean, contributing the third dimension to observations of this enigmatic world. The hypotheses REASON will test are that (1) the ice shell of Europa hosts liquid water, (2) the ice shell overlies an ocean and is subject to tidal flexing, and (3) the exosphere, near-surface, ice shell, and ocean participate in material exchange essential to the habitability of this moon. REASON will investigate processes governing this material exchange by characterizing the distribution of putative non-ice material (e.g., brines, salts) in the subsurface, searching for an ice-ocean interface, characterizing the ice shell's global structure, and constraining the amplitude of Europa's radial tidal deformations. REASON will accomplish these science objectives using a combination of radar measurement techniques including altimetry, reflectometry, sounding, interferometry, plasma characterization, and ranging. Building on a rich heritage from Earth, the moon, and Mars, REASON will be the first ice-penetrating radar to explore the outer solar system. Because these radars are untested for the icy worlds in the outer solar system, a novel approach to measurement quality assessment was developed to represent uncertainties in key properties of Europa that affect REASON performance and ensure robustness across a range of plausible parameters suggested for the icy moon. REASON will shed light on a never-before-seen dimension of Europa and - in concert with other instruments on Europa Clipper - help to investigate whether Europa is a habitable world.
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Affiliation(s)
| | - Alina Moussessian
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Elaine Chapin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Duncan A. Young
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | | | - Jeffrey J. Plaut
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Adam P. Freedman
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Dustin M. Schroeder
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305 USA
- Department of Geophysics, Stanford University, Stanford, CA 94305 USA
| | - Cyril Grima
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Gregor Steinbrügge
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Krista M. Soderlund
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Trina Ray
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Thomas G. Richter
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Laura Jones-Wilson
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | - Kirk M. Scanlan
- Geodesy & Earth Observation Division, DTU Space, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Christopher Gerekos
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Kristian Chan
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
- Department of Earth and Planetary Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712 USA
| | - Ilgin Seker
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Mark S. Haynes
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | | | - Bruce A. Campbell
- Smithsonian Institution, Center for Earth & Planetary Studies, MRC 315, Washington, DC 20013-7012 USA
| | - Lynn M. Carter
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 USA
| | - Charles Elachi
- California Institute of Technology, Pasadena, CA 91125 USA
| | - Yonggyu Gim
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Alain Hérique
- University Grenoble Alpes, CNRS, CNES, IPAG, 38000 Grenoble, France
| | - Hauke Hussmann
- Institute of Planetary Research, German Aerospace Center, Berlin, Germany
| | - Wlodek Kofman
- University Grenoble Alpes, CNRS, CNES, IPAG, 38000 Grenoble, France
- Centrum Badan Kosmicznych Polskiej Akademii Nauk (CBK PAN), Warsaw, Poland
| | - William S. Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 USA
| | | | | | | | - Francis Nimmo
- Dept. Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064 USA
| | - Carol Paty
- Department of Earth Sciences, University of Oregon, Eugene, OR 97403 USA
| | | | - Britney E. Schmidt
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - Mikhail Y. Zolotov
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 USA
| | | | - Simon Collins
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Harry Figueroa
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Mark Fischman
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Eric Tardiff
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Andy Berkun
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Mimi Paller
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | | | - Gregory A. Sadowy
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Kevin B. Wheeler
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Emmanuel Decrossas
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Yasser Hussein
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Curtis Jin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Frank Boldissar
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Neil Chamberlain
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Brenda Hernandez
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Elham Maghsoudi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jonathan Mihaly
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 USA
| | - Shana Worel
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Vik Singh
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Kyung Pak
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jordan Tanabe
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Robert Johnson
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Mohammad Ashtijou
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Tafesse Alemu
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Michael Burke
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Brian Custodero
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Michael C. Tope
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - David Hawkins
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Kim Aaron
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | | | - Donald L. Kirchner
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 USA
| | - Karthik Srinivasan
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Julie Xie
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Brad Ortloff
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Ian Tan
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Tim Noh
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Duane Clark
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Vu Duong
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Shivani Joshi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jeng Lee
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Elvis Merida
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Ruzbeh Akbar
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Xueyang Duan
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Ines Fenni
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | - Chaitali Parashare
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Duane C. Howard
- Center for Quantum Computing, Amazon Web Services, Pasadena, CA 91125 USA
| | | | - Marvin G. Cruz
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | | | - Ahmadreza Amirahmadi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Brendon Palmer
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Rohit S. Gawande
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Grace Milroy
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Rick Roberti
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Frank E. Leader
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Richard D. West
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jan Martin
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Vijay Venkatesh
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Virgil Adumitroaie
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Christine Rains
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Cuong Quach
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - Jordi E. Turner
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 USA
| | - Colleen M. O’Shea
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 USA
| | - Scott D. Kempf
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Gregory Ng
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Dillon P. Buhl
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
| | - Timothy J. Urban
- Institute for Geophysics, University of Texas at Austin, Austin, TX 78758 USA
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3
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Vance SD, Craft KL, Shock E, Schmidt BE, Lunine J, Hand KP, McKinnon WB, Spiers EM, Chivers C, Lawrence JD, Wolfenbarger N, Leonard EJ, Robinson KJ, Styczinski MJ, Persaud DM, Steinbrügge G, Zolotov MY, Quick LC, Scully JEC, Becker TM, Howell SM, Clark RN, Dombard AJ, Glein CR, Mousis O, Sephton MA, Castillo-Rogez J, Nimmo F, McEwen AS, Gudipati MS, Jun I, Jia X, Postberg F, Soderlund KM, Elder CM. Investigating Europa's Habitability with the Europa Clipper. SPACE SCIENCE REVIEWS 2023; 219:81. [PMID: 38046182 PMCID: PMC10687213 DOI: 10.1007/s11214-023-01025-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 11/03/2023] [Indexed: 12/05/2023]
Abstract
The habitability of Europa is a property within a system, which is driven by a multitude of physical and chemical processes and is defined by many interdependent parameters, so that its full characterization requires collaborative investigation. To explore Europa as an integrated system to yield a complete picture of its habitability, the Europa Clipper mission has three primary science objectives: (1) characterize the ice shell and ocean including their heterogeneity, properties, and the nature of surface-ice-ocean exchange; (2) characterize Europa's composition including any non-ice materials on the surface and in the atmosphere, and any carbon-containing compounds; and (3) characterize Europa's geology including surface features and localities of high science interest. The mission will also address several cross-cutting science topics including the search for any current or recent activity in the form of thermal anomalies and plumes, performing geodetic and radiation measurements, and assessing high-resolution, co-located observations at select sites to provide reconnaissance for a potential future landed mission. Synthesizing the mission's science measurements, as well as incorporating remote observations by Earth-based observatories, the James Webb Space Telescope, and other space-based resources, to constrain Europa's habitability, is a complex task and is guided by the mission's Habitability Assessment Board (HAB).
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Affiliation(s)
- Steven D. Vance
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Kathleen L. Craft
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD USA
| | - Everett Shock
- School of Earth & Space Exploration and School of Molecular Sciences, Arizona State University, Tempe, AZ USA
| | - Britney E. Schmidt
- Department of Astronomy and Department of Earth & Atmospheric Sciences, Cornell University, Ithaca, NY USA
| | - Jonathan Lunine
- Department of Astronomy and Department of Earth & Atmospheric Sciences, Cornell University, Ithaca, NY USA
| | - Kevin P. Hand
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - William B. McKinnon
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, Saint Louis, MO USA
| | - Elizabeth M. Spiers
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
| | - Chase Chivers
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
- Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA USA
| | - Justin D. Lawrence
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
- Honeybee Robotics, Altadena, CA USA
| | - Natalie Wolfenbarger
- Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, University of Texas at Austin, Austin, TX USA
| | - Erin J. Leonard
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | | | | | - Divya M. Persaud
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Gregor Steinbrügge
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Mikhail Y. Zolotov
- School of Earth & Space Exploration and School of Molecular Sciences, Arizona State University, Tempe, AZ USA
| | | | | | | | - Samuel M. Howell
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | | | - Andrew J. Dombard
- Dept. of Earth and Environmental Sciences, University of Illinois Chicago, Chicago, USA
| | | | - Olivier Mousis
- Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille), Marseille, France
| | - Mark A. Sephton
- Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, Imperial College London, London, United Kingdom
| | | | - Francis Nimmo
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA USA
| | - Alfred S. McEwen
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | - Murthy S. Gudipati
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Insoo Jun
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Xianzhe Jia
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI USA
| | - Frank Postberg
- Institut für Geologische Wissenschaften, Freie Universität Berlin, Berlin, Germany
| | - Krista M. Soderlund
- Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, University of Texas at Austin, Austin, TX USA
| | - Catherine M. Elder
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
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4
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Villanueva GL, Hammel HB, Milam SN, Faggi S, Kofman V, Roth L, Hand KP, Paganini L, Stansberry J, Spencer J, Protopapa S, Strazzulla G, Cruz-Mermy G, Glein CR, Cartwright R, Liuzzi G. Endogenous CO 2 ice mixture on the surface of Europa and no detection of plume activity. Science 2023; 381:1305-1308. [PMID: 37733858 DOI: 10.1126/science.adg4270] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 08/22/2023] [Indexed: 09/23/2023]
Abstract
Jupiter's moon Europa has a subsurface ocean beneath an icy crust. Conditions within the ocean are unknown, and it is unclear whether it is connected to the surface. We observed Europa with the James Webb Space Telescope (JWST) to search for active release of material by probing its surface and atmosphere. A search for plumes yielded no detection of water, carbon monoxide, methanol, ethane, or methane fluorescence emissions. Four spectral features of carbon dioxide (CO2) ice were detected; their spectral shapes and distribution across Europa's surface indicate that the CO2 is mixed with other compounds and concentrated in Tara Regio. The 13CO2 absorption is consistent with an isotopic ratio of 12C/13C = 83 ± 19. We interpret these observations as indicating that carbon is sourced from within Europa.
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Affiliation(s)
- G L Villanueva
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - H B Hammel
- Association of Universities for Research in Astronomy, Washington, DC 20004, USA
| | - S N Milam
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - S Faggi
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- American University, Washington, DC 20016, USA
| | - V Kofman
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- American University, Washington, DC 20016, USA
| | - L Roth
- Royal Institute of Technology, Stockholm 104 50, Sweden
| | - K P Hand
- Jet Propulsion Laboratory, Pasadena, CA 91109, USA
| | - L Paganini
- NASA Headquarters, Washington, DC 20546, USA
| | - J Stansberry
- Space Telescope Science Institute, Baltimore, MD 21218, USA
| | - J Spencer
- Southwest Research Institute, Boulder, CO 80302, USA
| | - S Protopapa
- Southwest Research Institute, Boulder, CO 80302, USA
| | - G Strazzulla
- Osservatorio Astrofisico di Catania, Istituto Nazionale di Astrofisica, 95123 Catania, Italy
| | - G Cruz-Mermy
- Universite Paris-Sarclay, 91190 Gif-sur-Yvette, France
| | - C R Glein
- Southwest Research Institute, San Antonio, TX 78238, USA
| | - R Cartwright
- Carl Sagan Center for Research, Search for Extraterrestrial Intelligence Institute, Mountain View, CA 94043, USA
| | - G Liuzzi
- Università degli Studi della Basilicata, 85100 Potenza, Italy
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5
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Roberts JH, McKinnon WB, Elder CM, Tobie G, Biersteker JB, Young D, Park RS, Steinbrügge G, Nimmo F, Howell SM, Castillo-Rogez JC, Cable ML, Abrahams JN, Bland MT, Chivers C, Cochrane CJ, Dombard AJ, Ernst C, Genova A, Gerekos C, Glein C, Harris CD, Hay HCFC, Hayne PO, Hedman M, Hussmann H, Jia X, Khurana K, Kiefer WS, Kirk R, Kivelson M, Lawrence J, Leonard EJ, Lunine JI, Mazarico E, McCord TB, McEwen A, Paty C, Quick LC, Raymond CA, Retherford KD, Roth L, Rymer A, Saur J, Scanlan K, Schroeder DM, Senske DA, Shao W, Soderlund K, Spiers E, Styczinski MJ, Tortora P, Vance SD, Villarreal MN, Weiss BP, Westlake JH, Withers P, Wolfenbarger N, Buratti B, Korth H, Pappalardo RT. Exploring the Interior of Europa with the Europa Clipper. SPACE SCIENCE REVIEWS 2023; 219:46. [PMID: 37636325 PMCID: PMC10457249 DOI: 10.1007/s11214-023-00990-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 07/20/2023] [Indexed: 08/29/2023]
Abstract
The Galileo mission to Jupiter revealed that Europa is an ocean world. The Galileo magnetometer experiment in particular provided strong evidence for a salty subsurface ocean beneath the ice shell, likely in contact with the rocky core. Within the ice shell and ocean, a number of tectonic and geodynamic processes may operate today or have operated at some point in the past, including solid ice convection, diapirism, subsumption, and interstitial lake formation. The science objectives of the Europa Clipper mission include the characterization of Europa's interior; confirmation of the presence of a subsurface ocean; identification of constraints on the depth to this ocean, and on its salinity and thickness; and determination of processes of material exchange between the surface, ice shell, and ocean. Three broad categories of investigation are planned to interrogate different aspects of the subsurface structure and properties of the ice shell and ocean: magnetic induction, subsurface radar sounding, and tidal deformation. These investigations are supplemented by several auxiliary measurements. Alone, each of these investigations will reveal unique information. Together, the synergy between these investigations will expose the secrets of the Europan interior in unprecedented detail, an essential step in evaluating the habitability of this ocean world.
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Affiliation(s)
| | | | - Catherine M Elder
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | | | | | - Ryan S Park
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Gregor Steinbrügge
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Francis Nimmo
- University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Samuel M Howell
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | - Morgan L Cable
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | | | | | - Corey J Cochrane
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | - Carolyn Ernst
- Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA
| | | | | | | | | | - Hamish C F C Hay
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Paul O Hayne
- University of Colorado Boulder, Boulder, CO, USA
| | | | - Hauke Hussmann
- German Aerospace Center Institute of Planetary Research, Berlin, Germany
| | | | | | - Walter S Kiefer
- Lunar and Planetary Institute, University Space Research Association, Houston, TX, USA
| | | | | | | | - Erin J Leonard
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | | | | | | | | | | | - Carol A Raymond
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Kurt D Retherford
- Sapienza University of Rome, Rome, Italy
- University of Texas at San Antonio, San Antonio, TX, USA
| | - Lorenz Roth
- KTH Royal Institute of Technology, Stockholm, Sweden
| | - Abigail Rymer
- Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA
| | | | | | | | - David A Senske
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Wencheng Shao
- University of California, Santa Cruz, Santa Cruz, CA, USA
| | | | | | - Marshall J Styczinski
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
- University of Washington, Seattle, WA, USA
| | - Paolo Tortora
- Alma Mater Studiorum - Università di Bologna, Bologna, Italy
| | - Steven D Vance
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | | | | | | | | | - Bonnie Buratti
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Haje Korth
- Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA
| | - Robert T Pappalardo
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
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6
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Morrison AA, Whittington AG, Mitchell KL. A Reevaluation of Cryolava Flow Evolution: Assumptions, Physical Properties, and Conceptualization. JOURNAL OF GEOPHYSICAL RESEARCH. PLANETS 2023; 128:e2022JE007383. [PMID: 37034461 PMCID: PMC10078481 DOI: 10.1029/2022je007383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 06/19/2023]
Abstract
Cryovolcanism has been invoked to explain numerous features observed on icy bodies. Many of these features show similar morphologies to volcanic features observed on Earth suggesting similar physics involved in their formation. Cryovolcanism lies at the intersection of volcanology and hydrology but as such, no one model from either discipline satisfactorily represents cryolava flow emplacement. We produced a new model for cryolava flow evolution that draws from both disciplines to track the physical, chemical, and thermal states of a hypothetical H2O-NaCl flow on a Europa-like body as it evolves away from the vent. This model is currently restricted to compositions on the water-rich side of this chemical system and only predicts emplacement up to the turbulent to laminar transition. Modeling the laminar regime and a broader compositional space will be dealt with separately. Concentrations between 5 and 23 wt% (H2O-NaCl eutectic) and initial flow thicknesses of 0.1, 1, 10, and 100 m were set as initial conditions. Model results suggest that flow may reach 40-60 vol% solids before transitioning to laminar flow. The thermal budget for these flows is dominated by the heat loss from vaporization in the low-pressure environment. This model produces length to thickness aspect ratios, for the given compositions, that are broadly consistent with candidate cryovolcanic features on Ceres and Titan. These first-order comparisons are not ideal and suggest the need for future modeling of cryovolcanic features in at least two dimensions.
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Affiliation(s)
- Aaron A. Morrison
- Department of Geological SciencesThe University of Texas at San AntonioSan AntonioTXUSA
| | - Alan G. Whittington
- Department of Geological SciencesThe University of Texas at San AntonioSan AntonioTXUSA
| | - Karl L. Mitchell
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
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7
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Instrumentation for Detecting Sulphur Isotopes as Biosignatures on Europa and Ganymede by Forthcoming Missions. UNIVERSE 2022. [DOI: 10.3390/universe8070357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
There has been remarkable progress in identifying a certain type of biosignature, both from the point of view of the payloads of forthcoming missions, and from the point of view of biogeochemistry. This progress has been due to the evolution of miniaturized mass spectrometry that can be used, under certain circumstances and for certain samples, to distinguish between putatively abiotic and biotic sulphur isotopes. These specific types of biosignatures are discussed in the context of Europa and Ganymede. Such instruments are sufficiently precise to differentiate between abiotic and biotic signatures. We reflect on new possibilities that will be available during this decade for exploring the nearest ocean worlds: Europa and Ganymede. We review arguments that point out the presence of intriguing sulphur patches on Europa’s icy surface that were discovered by the Galileo mission. These patches lead to a “sulphur dilemma”, which suggests not to focus future measurements exclusively on organics. We comment on the possibility of measurements of sulphur isotopes, as one kind of biosignature, to be complemented with additional biosignatures, in order to fully test biogenicity. These suggestions are intended to point out the best use of the available spacecrafts’ payloads during the planning of the forthcoming Jovian missions.
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8
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The 3D Direct Simulation Monte Carlo Study of Europa’s Gas Plume. UNIVERSE 2022. [DOI: 10.3390/universe8050261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Europa has been spotted as having water outgassing activities by space- and ground-based telescopes as well as reanalysis of the Galileo data. We adopt a 3D Direct Simulation Monte Carlo (DSMC) model to investigate the observed plume characteristics of Europa assuming that supersonic expansion originated from the subsurface vent. With a parametric study of the total gas production rate and initial gas bulk velocity, the gas number density, temperature and velocity information of the outgassing plumes from various case studies were derived. Our results show that the plume gases experience acceleration through mutual collisions and adiabatic cooling when exiting from the surface. The central part of the plume with relatively large gas production rates (1029 and 1030 H2O s−1) was found to sustain thermal equilibrium and near continuum condition. Column density maps integrated along two different viewing angles are presented to demonstrate the importance of the projection effect on remote sensing diagnostics. Finally, the density profiles at different altitudes are provided to prepare for observations of Europa’s plumes including upcoming spacecraft missions such as JUICE and Europa Clipper.
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9
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Culberg R, Schroeder DM, Steinbrügge G. Double ridge formation over shallow water sills on Jupiter's moon Europa. Nat Commun 2022; 13:2007. [PMID: 35440535 PMCID: PMC9018861 DOI: 10.1038/s41467-022-29458-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 02/24/2022] [Indexed: 11/09/2022] Open
Abstract
Jupiter's moon Europa is a prime candidate for extraterrestrial habitability in our solar system. The surface landforms of its ice shell express the subsurface structure, dynamics, and exchange governing this potential. Double ridges are the most common surface feature on Europa and occur across every sector of the moon, but their formation is poorly understood, with current hypotheses providing competing and incomplete mechanisms for the development of their distinct morphology. Here we present the discovery and analysis of a double ridge in Northwest Greenland with the same gravity-scaled geometry as those found on Europa. Using surface elevation and radar sounding data, we show that this double ridge was formed by successive refreezing, pressurization, and fracture of a shallow water sill within the ice sheet. If the same process is responsible for Europa's double ridges, our results suggest that shallow liquid water is spatially and temporally ubiquitous across Europa's ice shell.
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Affiliation(s)
- Riley Culberg
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA.
| | - Dustin M Schroeder
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA.,Department of Geophysics, Stanford University, Stanford, CA, USA
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10
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Singer KN, White OL, Schmitt B, Rader EL, Protopapa S, Grundy WM, Cruikshank DP, Bertrand T, Schenk PM, McKinnon WB, Stern SA, Dhingra RD, Runyon KD, Beyer RA, Bray VJ, Ore CD, Spencer JR, Moore JM, Nimmo F, Keane JT, Young LA, Olkin CB, Lauer TR, Weaver HA, Ennico-Smith K. Large-scale cryovolcanic resurfacing on Pluto. Nat Commun 2022; 13:1542. [PMID: 35351895 PMCID: PMC8964750 DOI: 10.1038/s41467-022-29056-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 02/09/2022] [Indexed: 11/09/2022] Open
Abstract
The New Horizons spacecraft returned images and compositional data showing that terrains on Pluto span a variety of ages, ranging from relatively ancient, heavily cratered areas to very young surfaces with few-to-no impact craters. One of the regions with very few impact craters is dominated by enormous rises with hummocky flanks. Similar features do not exist anywhere else in the imaged solar system. Here we analyze the geomorphology and composition of the features and conclude this region was resurfaced by cryovolcanic processes, of a type and scale so far unique to Pluto. Creation of this terrain requires multiple eruption sites and a large volume of material (>104 km3) to form what we propose are multiple, several-km-high domes, some of which merge to form more complex planforms. The existence of these massive features suggests Pluto’s interior structure and evolution allows for either enhanced retention of heat or more heat overall than was anticipated before New Horizons, which permitted mobilization of water-ice-rich materials late in Pluto’s history. Giant icy volcanos (cryovolcanos) on Pluto are unique in the imaged solar system and provide evidence for unexpected, active geology late in Pluto’s history.
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11
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12
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13
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Ruesch O, Platz T, Schenk P, McFadden LA, Castillo-Rogez JC, Quick LC, Byrne S, Preusker F, O’Brien DP, Schmedemann N, Williams DA, Li JY, Bland MT, Hiesinger H, Kneissl T, Neesemann A, Schaefer M, Pasckert JH, Schmidt BE, Buczkowski DL, Sykes MV, Nathues A, Roatsch T, Hoffmann M, Raymond CA, Russell CT. Cryovolcanism on Ceres. Science 2016; 353:353/6303/aaf4286. [DOI: 10.1126/science.aaf4286] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 07/20/2016] [Indexed: 11/02/2022]
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14
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Roth L, Saur J, Retherford KD, Strobel DF, Feldman PD, McGrath MA, Nimmo F. Transient Water Vapor at Europa’s South Pole. Science 2014; 343:171-4. [DOI: 10.1126/science.1247051] [Citation(s) in RCA: 326] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Lorenz Roth
- Southwest Research Institute, San Antonio, TX, USA
- Institute of Geophysics and Meteorology, University of Cologne, Germany
| | - Joachim Saur
- Institute of Geophysics and Meteorology, University of Cologne, Germany
| | | | - Darrell F. Strobel
- Department of Earth and Planetary Science, The Johns Hopkins University, Baltimore, MD, USA
- Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD, USA
| | - Paul D. Feldman
- Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD, USA
| | | | - Francis Nimmo
- Department of Earth and Planetary Sciences, University of California Santa Cruz, CA, USA
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15
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Pappalardo RT, Vance S, Bagenal F, Bills BG, Blaney DL, Blankenship DD, Brinckerhoff WB, Connerney JEP, Hand KP, Hoehler TM, Leisner JS, Kurth WS, McGrath MA, Mellon MT, Moore JM, Patterson GW, Prockter LM, Senske DA, Schmidt BE, Shock EL, Smith DE, Soderlund KM. Science potential from a Europa lander. ASTROBIOLOGY 2013; 13:740-773. [PMID: 23924246 DOI: 10.1089/ast.2013.1003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The prospect of a future soft landing on the surface of Europa is enticing, as it would create science opportunities that could not be achieved through flyby or orbital remote sensing, with direct relevance to Europa's potential habitability. Here, we summarize the science of a Europa lander concept, as developed by our NASA-commissioned Science Definition Team. The science concept concentrates on observations that can best be achieved by in situ examination of Europa from its surface. We discuss the suggested science objectives and investigations for a Europa lander mission, along with a model planning payload of instruments that could address these objectives. The highest priority is active sampling of Europa's non-ice material from at least two different depths (0.5-2 cm and 5-10 cm) to understand its detailed composition and chemistry and the specific nature of salts, any organic materials, and other contaminants. A secondary focus is geophysical prospecting of Europa, through seismology and magnetometry, to probe the satellite's ice shell and ocean. Finally, the surface geology can be characterized in situ at a human scale. A Europa lander could take advantage of the complex radiation environment of the satellite, landing where modeling suggests that radiation is about an order of magnitude less intense than in other regions. However, to choose a landing site that is safe and would yield the maximum science return, thorough reconnaissance of Europa would be required prior to selecting a scientifically optimized landing site.
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Affiliation(s)
- R T Pappalardo
- Planetary Sciences Section, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
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16
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Mora MF, Stockton AM, Willis PA. Microchip capillary electrophoresis instrumentation for in situ analysis in the search for extraterrestrial life. Electrophoresis 2012; 33:2624-38. [DOI: 10.1002/elps.201200102] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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17
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Greenberg R. Transport rates of radiolytic substances into Europa's ocean: implications for the potential origin and maintenance of life. ASTROBIOLOGY 2010; 10:275-283. [PMID: 20446868 DOI: 10.1089/ast.2009.0386] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Abstract Bombardment of the surface of Europa produces oxidants and other biologically useful substances, but they can only contribute to the habitability of the ocean if they are delivered down through the icy crust. Previous estimates of the thickness of the oxygenated layer of ice assumed that impact gardening is the dominant factor and concluded that the ocean may be habitable if the oxidant delivery time, via undefined mechanisms, is sufficiently short. Consideration of the types of processes that continually resurface Europa suggests that the oxygenated layer is thicker than approximately 300 m, far greater than the few meters indicated by impact gardening alone, and possibly includes the entire ice crust. The estimated delivery rate to the ocean is such that the oxygen levels could now be high enough to support macrofauna; and, at approximately 3 x 10(11) mol/yr of oxygen, it could maintain 3 million tons of macrofauna, assuming respiration rates similar to terrestrial marine organisms. These values are independent of any additional contributions due to possible photosynthesis. Initial formation of life would be difficult with so much oxygen, but the start of oxidant delivery into the ocean would have been delayed by 1-2 billion years while the crust became loaded with oxidants. In the ocean, this delay would have allowed time for prebiotic assemblages and anaerobic biological development prior to the increasing oxidant concentration to otherwise toxic levels.
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Affiliation(s)
- Richard Greenberg
- Lunar and Planetary Laboratory, University of Arizona, 1629 East University Blvd., Tucson, AZ 85721-0092, USA.
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18
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Manga M. Formation of bands and ridges on Europa by cyclic deformation: Insights from analogue wax experiments. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2004je002249] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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